52 THE SKELETON OF THE CAT. 
A portion of the floor of the orbit and the opening of the 
lachrymal canal (0) may also be seen in dorsal view; they are 
described in connection with the lateral surface. 
The caudal surface of the skull is formed largely by the 
occipital bone (Fig. 17), surrounding the foramen magnum 
(Fig. 17, 2). At the sides of the foramen magnum are the 
two prominent curved occipital condyles (¢) for articulation 
with the atlas. Craniolaterad of the condyles, separated from 
them by a deep notch, are the jugular processes (/) of the 
occipital, closely applied to the caudal ends of the tympanic 
bulla. 
Dorsad of the foramen magnum are faint indications of a 
median ridge running dorsad, the external occipital crest 
(Fig. 17,2); this rises at its junction with the lambdoidal ridge 
to form the prominent external occipital tubercle (Fig. 39, 2). 
The dorsal and dorsolateral boundaries of the posterior surface 
are formed by the lambdoidal ridge (Fig. 17, 4; Fig. 39, a). 
The lateral surface of the skull (Fig. 40) is much more 
complicated than the dorsal and posterior surfaces. Caudally 
the occipital condyles (a) and external occipital crest (4) are 
visible; dorsocaudad the sagittal crest (c). 
Extending from the caudal end of the sagittal crest the 
lambdoidal ridge (d@) is seen passing ventrocraniad to the tym- 
panic bulla, thence craniad to the root of the zygomatic arch. 
In the ventral part of the caudal region the tympanic bulla (e) 
is visible with the jugular process (/) of the occipital pressed 
close against its caudal end. Just craniad of the jugular process 
the mastoid process (g) of the temporal rests against the side 
of the bulla. Beneath the cranial edge of this process is the 
opening of the stylomastoid foramen (/) for the seventh nerve, 
while just ventrad of the foramen is the small pit (2) in the 
tympanic bulla for the reception .of the tympanohyal bone. 
Craniad of the stylomastoid foramen is the large opening of the 
external auditory meatus (7), leading into the middle ear. 
Immediately dorsocraniad of the external auditory meatus 
the zygomatic arch begins as the zygomatic process_(£) of the 
temporal bone. On the cranial surface of the base of this 
process is the deep mandibular fossa (/) for the condyle of the 
